Abstract:The basic roof breaking has an important effect on the working face weighting. In order to study the breaking mechanism of the basic roof, according to the boundary condition of the initial breaking and periodic breaking of the roof, the mechanical models of three edges fixed-one edge simply supported plate and four edges fixed plate were established. The stress distribution characteristics and breaking mechanism of the basic roof breaking were analyzed by means of the Galerkin method. The theoretical solutions of the maximum bending moment were deduced. Through the breaking criterion the roof breaking position and weighting step were obtained. The results show that the basic roof breaking was related to the overburden load, the length and advancing distance of working face, the roof thickness, the Poisson ratio, not related to the elastic modulus. The roof weighting step of field observations and theoretical results were in good agreement, which can provide the basis for the forecasting of the roof weighting.